1. Field of the Invention
The present invention relates to an input detection device, an input detection method, and a computer readable media, and in particular relates to an input detection method, and a computer readable media, for detecting touch inputs from an interface of a touch sensor provided with electrodes arranged in a matrix.
2. Description of the Related Art
A differential detection method where two detection electrodes are utilized is well-known for the touch sensor field. The differential detection method is an algorithm, where a touch input is detected from an interface of a touch sensor by acquiring a difference of two detection data. Here, when a plurality of detection electrodes extending in a horizontal or vertical direction in the touch sensor are scanned in sequence, one detection data is obtained from a detection electrode, and the other one is obtained from a reference electrode disposed individually with the detection electrodes or an electrode chosen from the detection electrodes (for example, Patent document 1, Japanese Patent Application Publication no. H05-6153, and Patent document 2, U.S. Patent Application Publication no. 2010/0060610A1). According to the algorithm, influence from surrounding noise (for example, LCD driving noise) may be reduced while input detection.
The differential detection method can also be applied to a touch sensor capable of multi-touch input detection. In U.S. Patent Application Publication no. 2009/0273579A1 (Patent document 3), a method, detecting inputs by scanning every two electrodes which are not adjacent but extended in parallel and then acquiring the difference between data detected from the two electrodes, is disclosed.
Patent document 1: Japanese Patent Application Publication no. H05-6153
Patent document 2, U.S. Patent Application Publication no. 2010/0060610A1
Patent document 3, U.S. Patent Application Publication no. 2009/0273579A1
However, when the differential detection method is applied to a touch sensor capable of multi-touch input detection, in the case where two electrodes to be acquired with a difference of detection data are applied with one of multi-touch inputs respectively, the difference cannot be acquired from the data detected from the two electrodes correctly. As a result, multi-touch inputs cannot be detected correctly.
In recent years, multi-touch screens have been popularly utilized in devices like smart phones. If multi-touch inputs are not detected correctly, a pinch in action wherein two fingers griping an operable object on the screen are moved toward each other to minify the picture, or a pinch out action wherein two fingers are moved away from each other to magnify the picture may not be identified correctly, causing the device to make a wrong response.
The purpose of the invention is to provide an input detection device, an input detection method, and a computer readable media capable of correctly detecting multi-touch inputs with a differential detection algorithm.